interface Alarm {
  alert(): void;
}

interface Light {
  lightOn(): void;
  lightOff(): void;
}

class Door {
}

class SecurityDoor extends Door implements Alarm {
  alert() {
      console.log('SecurityDoor alert.');
  }
}

class Car implements Alarm, Light {
  alert() {
      console.log('Car alert.');
  }
  
  lightOn() {
      console.log('Car light on.');
  }
  
  lightOff() {
      console.log('Car light off.');
  }
}